TITLE:
Antimicrobial Properties of Actinomycetes Isolated from Menengai Crater in Kenya
AUTHORS:
Paul Njenga Waithaka, Francis B. Mwaura, John M. Wagacha, Eliud M. Gathuru, Benson M. Githaiga
KEYWORDS:
Actinomycetes, Antimicrobials, Crater, Menengai, Metabolites, Sensitivity
JOURNAL NAME:
CellBio,
Vol.6 No.2,
June
30,
2017
ABSTRACT: A study was carried
out to isolate and screen actinomycetes for antimicrobials from Menengai Crater
in Kenya. The actinomycetes were isolated using starch casein agar, Luria
Bertani agar and starch nitrate agar. Primary screening for antagonism was
carried out using perpendicular method while secondary screening was done using
agar disk technique. Extraction of the antimicrobials was carried out using
ethyl acetate. Sensitivity testing of the crude extracts against Staphylococcus aureus, Bacillus subtilis, Escherichia faecalis, Escherichia
coli, Klebsiella pneumoniae, Salmonella typhi, Xanthomonas campestris, Erwinia carotovora, Candida albicans, Alternaria alternate and Fusarium oxysporum was carried out using agar well technique. Biochemical tests and carbon source
requirements were used in characterization of the selected antimicrobial
producers. M1 was the best agar medium for isolation of actinomycetes. The
number of actinomycetes from regions A, B, C, and D in the crater varied
significantly (F = 27.50 P = 0.000).
Out of the 156 actinomycetes isolates, 20 isolates were positive for both
primary and secondary screening for antimicrobials. There was no significant
difference in the zones of inhibition in primary screening of the actinomycetes
for antagonistic properties against the test pathogens (F = 1.6957 P = 0.0838). The zones of inhibition
after secondary screening varied significantly (F = 2.4473 P = 0.0089). Likewise, there was a significant difference (F =
6.6046 P = 0.001338) in the zones of
inhibition after exposing the pathogens to ethyl extracts of the selected
antagonistic actinomycetes. There is need to purify and characterize the
antimicrobials obtained from the present study.